Air breather assembly

ABSTRACT

An air breather for mounting on a container wall having an opening has a first loaded valve permitting outflow of air when a certain internal pressure is exceeded, and a second loaded valve permitting inflow of air when a certain lowering of internal pressure below atmospheric is exceeded, the first valve including a movable apertured housing acting as a valve member and cooperating with a valve seating, and the second valve having a movable resiliently deformable flange acting as a valve member and cooperating with the apertured housing serving as a seating.

United States Patent 1191 Button 5] Jan. 15, 1974 AIR BREATHER ASSEMBLY I [75] inventor: David Button, Bury St. Edmonds, Primary Exami7erEdgar Gefghegan England Asszstant Exammer-Robert J. M1ller Attorney-William Anthony Drucker [73] Assignee: U.C.C Hydraulics Limited, Norfolk,

g 57 ABSTRACT [22] Ffled: i 1972 An air breather for mounting on a container wall hav- [21 Appl. No.: 263,942 v ing an opening has a first loaded valve permitting out- I flow of air when a Certain internal pressure is ex- 1521 us. (:1. 137/493.2, 137/493.8 'i f a 3 ";1 i" inflow 511 1111.01. F16k 17/26, Fl6k 45/00 8 '1 1? a ga: f f i g 58 Field of Search"; 137/4932, 493.8, em e I e u I r 137/525 525 3 ing a movable apertured housmg actmg as a valve member and cooperating with a valve seating, and the [56] References Cited second valve having a movable resiliently deformable flange acting as a valve member and cooperating with UNITED STATES PATENTS the apertured housing serving'as a seating. 3,414,334 12/1968 Payne 137/4932 2,133,575 10/1938 Rosenberg 137/4932 3 Clam, 2 Flgures 1 AIR BREATHER ASSEMBLY This invention relates to an air breather assembly, its object being to provide an improved construction of that kind of breather assembly which permits a container, on which the'breather assembly is mounted, to be pressurized to greater than atmospheric pressure, whilst nevertheless permitting intake of atmospheric air if the internal pressure of the container should pass below atmospheric. I

According to the present invention an air breather assembly comprises an apertured mounting for securing over an opening of a wall of a container, a cap engageable onto and disengageable from said mounting by relative rotation, means for forming a fluid-tight seal between the mounting and the cap when engaged thereon, saidcap defining an air flow .path between its exterior and the aperture'of the mounting, first valve means resiliently loaded in the closing direction disposed in the cap and positioned across said path and adapted normally to close said path against outward flow of air'to atmosphere unless a certain pressure is exceeded, said first valve means having as its movable valve member an apertured housing which is urged by spring means against a valve seating, and second valve means resiliently loaded in the closing direction disposed in the cap and positioned across said path and adapted normally to close said path against inward flow of air from atmosphere unless a certain pressure is exceeded, said second valve means having as its movable means a resiliently deformable flange positioned within the housing and overlying and normally sealing the aperturing of the housing.

Such a breather assembly could be utilised, by way of example, on a tank for liquid. By suitable choice of loading of the first valve means, the tank may be pressurized to, for example, 5 pounds per square inch above atmospheric pressure. :This internal pressure could provide a boost input pressure for a pump utilised to pump liquid from the tank away to a delivery point or round a closed circuit. Such an internal pressure in the tank also tends to exclude any foreign matter getting into the tank, and also tends to eliminate pump cavitation and thusleads to longer pump life and higher pumping efficiency. Nevertheless, when it is necessary for atmospheric air to pass into the tank, e.g.,

to replace a volume of liquid withdrawn, the second valve means can open to allow entry of air.

The seating may be formedby a radial flange of a stem secured to a baseplate of the cap, the housing being slidable axially on said stem. The resiliently deformable flange may be formed integrally with a resiliently deformable sleeve engaged on said stem.

An embodiment of pressurized air breather assembly for a tank, in accordance withthe invention, is hereinafter particularly described with reference to the ac- The strainer has a top flange .6 which is seated by a gasket 7 on the outer face of the tank wall. On the flange is placed another gasket 8 on which is seated a flange 9 of a mounting 10. On an annular shoulder 11 of the mounting there is positioned a gasket 12 which is secured to the underface of a baseplate 13 of a removable breather cap 14.

The breather cap is engageable onto, and removable from, the mounting 10 by partial rotation of the breather cap with respect to the mounting, thereby to bring opposed radial arms (not shown) on the cap into and out of engagement with undercut camming surfaces (not shown) on the mounting 10. The manner of engagement of the cap and mounting is conventional and will be well known to those skilled in the airbreather-and oil-filler arts under the description bayonet plate and cap connection, and need not be further describedherein as it does not constitute part of the presentinvention. It is sufficient to indicate that, by rotation of the cap through part of a whole turn anticlockwise, viewed from the top of the sheet in this drawing, the cap maybe removed from the mounting, andthe point of separation is the point of contact between the gasket 12 and the shoulder 11.

The interior of the cap is'divided into chambers 15 and 116 by a cylindrical filter sleeve 17. Chamber l6 communicates with the external atmosphere through a series of openings 18 formed at intervals round the baseplate 13.

Within the chamber 15 there is disposed valve means 19, shown in detail in FIG. 2. The valve means comprises a fixed stem 20 secured in position to the baseplate 13 by means of a screw 21 threaded into a boss 22 of the stem. The stem has a rigid radial flange 23 forming a valve seating, and an air-tight seal is provided between the flange 23 and the baseplate 13 by an O- ring 24.

On the stem 20 there is slidably mounted a housing 25 which is urged downwardly by a coiled compression spring 26 secured by a screw 27 threaded into the stem. The housing 25 constitutes the movable valve member of the first valve means referred to above. To provide a sealbetween the peripheral rim 28 of the housing 25, and the flange 23, there is provided an O-ring 29.

To provide a path of communication between the chamber 15 and the interior-of the tank (through the strainer 3) the housing 25 is apertured at 30, the flange 23 is apertured at 31, and the baseplate 13 is apertured at 32. This path of communication is normally closed by the resiliently deformable flange 33 of a rubber valve sleeve 34. The flange 33 thus constitutes the movable valve member of the second valve means referred to above. Thus, the cap 14, when rotated into proper engagement with the mounting 10, provides an air-tight closure for the aperture 2 of the tank, and the tank can be pressurised to a suitable greater than atmospheric pressure, e.g., 5 psi.

Nevertheless, in the event that such a quantity of liquid is withdrawn from the tank that the pressure in the tank passes to below atmospheric, the rubber flange 33 can deform inwardly and allow' entry of atmospheric arr.

If the pressure within the tank should exceed the desired maximum pressure determined by the strength of the spring 26, the housing25 lifts, with compression of the spring 26, and the excess air escapes between the rim 28 and the O-ring 29.

The screw 21 serves also to secure a tab 35 for connection of a chain 36 coupled at its other end (not shown) to the mounting l0, thereby to make the cap captive" but removable.

I claim:

1. An air breather assembly, for mounting on a container wall having an opening, comprising an apertured mounting for securing over said opening, a cap, means on said mounting and on said cap whereby said cap is engageable onto and disengageable from said mounting by relative rotation, means positioned between said mounting and said cap for forming a fluid-tight seal therebetween when said cap is engaged on said mounting, means in said cap defining an air flow path between its exterior and the aperture of the mounting, first valve means disposed in said cap and positioned across said path and adapted to close said path against outward flow of air, means resiliently loading said first valve means and normally holding said valve means in closing position unless certain pressure is exceeded, said first valve means including a movable valve member in the form of an apertured housing urged by said loading means against a valve seating, and second valve means I disposed in said cap and positioned across said path and adapted to close said path against inward flow of air from atmosphere, said second valve means including a movable valve member in the form of a resiliently deformable flange positioned within said housing and arranged in its unstressed condition to overlie and thereby close the aperturing of said housing unless and until a sufficient pressure is'applied inwardly from atmosphere to deform it away from said housing and thereby open said aperturing.

2. An air breather assembly, as claimed in claim 1, wherein said cap comprises a baseplate and a stem, said housing being slidable axially on said stem, and said seating of said second valve means being a radial flange on said stem.

3. An air breather assembly, as claimed in claim 2, comprising a resiliently deformable sleeve engaged on said stem and integral with said resiliently deformable flange. 

1. An air breather assembly, for mounting on a container wall having an opening, comprising an apertured mounting for securing over said opening, a cap, means on said mounting and on said cap whereby said cap is engageable onto and disengageable from said mounting by relative rotation, means positioned between said mounting and said cap for forming a fluid-tight seal therebetween when said cap is engaged on said mounting, means in said cap defining an air flow path between its exterior and the aperture of the mounting, first valve means disposed in said cap and positioned across said path and adapted to close said path against outward flow of air, means resiliently loading said first valve means and normally holding said valve means in closing position unless certain pressure is exceeded, said first valve means including a movable valve member in the form of an apertured housing urged by said loading means against a valve seating, and second valve means disposed in said cap and positioned across said path and adapted to close said path against inward flow of air from atmosphere, said second valve means including a movable valve member in the form of a resiliently deformable flange positioned within said housing and arranged in its unstressed condition to overlie and thereby close the aperturing of said housing unless and until a sufficient pressure is applied inwardly from atmosphere to deform it away from said housing and thereby open said aperturing.
 2. An air breather assembly, as claimed in claim 1, wherein said cap comprises a baseplate and a stem, said housing being slidable axially on said stem, and said seating of said second valve means being a radial flange on said stem.
 3. An air breather assembly, as claimed in claim 2, comprising a resiliently deformable sleeve engaged on said stem and integral with said resiliently deformable flange. 